如何摆脱日志文件中的^ M

Question

I am new to python. I am using a telnet connection in one file telnet.py and logging in another file debug.py . But after a successful telnet connection when I looked at the log file, I see ^M added in every line of log file. Can someone guide me through this to get rid of ^M in log file? Thanks in advance.

filename: telnet.py

tn = telnetlib.Telnet(HOST)
cmdout = tn.read_until(b"ogin")
Logging(str(cmdout))
tn.write(user.encode('ascii') + b"\r")

filename: debug.py

LOG_FILE = 'testing.log'
logging.basicConfig(filename=LOG_FILE, level=logging.DEBUG, format='% 
                    (asctime)s: %(levelname)s: %(message)s')

log = logging.getLogger()
def Logging(msg):
    log.debug(msg)

Logfile logs are below:

switch login
2019-03-22 11:33:37,623: DEBUG: : Password:
2019-03-22 11:33:37,927: DEBUG:  ^M
^M
Establishing connection...   Please wait.^M
^M
   *****************************************************^M
   *                                                   *^M
   *       Command Line Interface SHell  (CLISH)       *^M

Answer 1

When receiving a message, simply trim any \\r\\n and add the \\n back on.

def Logging(msg):
    msg = msg.rstrip('\r\n') + '\n'
    log.debug(msg)

If the message could be multiple lines, split and reassemble:

def Logging(msg):
    lines = [line.rstrip('\r') for line in msg.split('\n')]
    msg = '\n'.join(lines)
    log.debug(msg)

Answer 2

Using re you can find, and then replace the strings that match with a pattern. re.sub does this perfectly well for you.

import re 

string = "This is a ^M sample ^M string ^M."
pattern = r'\^M'
res = re.sub(pattern, "", string)

print(res, string)

Answer 3

You can read your log file, and use the replace method in python:

def remove_caret_m_from_the_old_log_file_and_create_a_new_log_file_without_it():
    # Read the old log file.
    the_file = open("your_log_file.txt", "r")
    initial_content = the_file.read()

    # Remove '^M'.
    desired_content = initial_content.replace('^M', '')

    # Write the new content into a new log file.
    the_new_file = open('your_new_log_file.txt', 'x')
    the_new_file.write(desired_content)